1. Field of the Invention
The present invention relates to a light emitting diode driving apparatus capable of maintaining a uniform current balance between light emitting diode channels.
2. Description of the Related Art
Recently, interest in and a demand for light emitting diodes (LEDs) has increased.
Since a device using a light emitting diode may be manufactured to be compact, it may be used even in a location in which it is difficult for an existing electronic product to be installed. In the case in which a device using the light emitting diode is used as a general lighting device, since light of varied colors and illumination intensities may easily be implemented in a device using the light emitting diode, it may be used in a lighting device or system suitable for use in a situation such as displaying a movie, reading a book, holding a meeting, or the like.
In addition, a lighting device or system using the light emitting diode consumes an amount of power corresponding to ⅛ of that consumed by an incandescent lamp, has a lifespan of 50 to 100 thousand hours, corresponding to a lifespan 5 to 10 times that of an incandescent lamp, is a mercury-free light source, is environmentally-friendly, and may be variably implemented.
Due to these characteristics, a light emitting diode lighting business has been promoted through national policy initiatives in countries such as Korea, the USA, Japan, Australia, and others.
Moreover, in accordance with the recent development of flat panel display technology, a flat panel display has also been used for automobile dashboard displays, as well as for smart phones, game machines, and digital cameras. In the future, the use of flat panel displays is projected to increase in fields related to personal life, such as in ultrathin-type televisions, transparent navigation devices, and the like. Further, in the current display field, new flat panel displays (FPDs), reflecting the requirements of the multimedia age, such as high resolution, large screens, and the like, have mainly been developed. Particularly, in the case of a large display, a liquid crystal display (LCD) TV has rapidly been developed, such that it will be expected that LCDs will play a leading role in the development of many products in view of the cost and marketability thereof in the future.
A thin film transistor liquid crystal display (TFT-LCD) is mainly used in a flat panel display. The TFT-LCD includes a backlight unit emitting light, and mainly uses a cold cathode fluorescent lamp (CCFL) as a backlight light source. However, recently, the use of a light emitting diode (LED) has been gradually increased due to various strengths such as low power consumption, long lifespan, environmental-friendliness characteristics, and the like. Therefore, a configuration of a low-cost and low-power electronics system for a backlight unit power module using an LED and an appropriate controlling element therefore have been urgently demanded.
As described above, a light emitting diode that tends to be increasingly used requires a driving apparatus for driving the light emitting diode. According to the related art, a switching element has mainly been used in order to control respective LED channels with a constant current. However, as disclosed in the following related art document, since respective LED channels are configured to include a plurality of LEDs connected in series, thereby causing a voltage deviation between the LEDs, current unbalance is generated between the LED channels, such that brightness of the light emitting diode driving apparatus may not be uniform.